tandem bicycle vs tandem

tandem bicycle and tandem both are nouns.

Word	Noun	Adjective	Verb	Adverb
tandem bicycle	Yes	No	No	No
tandem	Yes	No	No	Yes

As nouns, tandem bicycle and tandem are synonyms defined as:

tandem bicycle and tandem: a bicycle with two sets of pedals and two seats

Other synonyms of tandem bicycle include bicycle-built-for-two.

tandem bicycle (noun)	tandem (noun)
a bicycle with two sets of pedals and two seats	a bicycle with two sets of pedals and two seats
	an arrangement of two or more objects or persons one behind another

tandem bicycle (adverb)	tandem (adverb)
	one behind the other